Lysosomal storage disorders: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Biochemistry · Lysosomal storage disorders

Sample item

A 12-year-old boy has burning pain in the hands and feet, dark red spots on the skin of the trunk and proteinuria. His maternal uncle died of renal failure. Which enzyme is deficient?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Alpha-galactosidase A

Fabry disease is X-linked and results from alpha-galactosidase A deficiency, with accumulation of ceramide trihexoside. It causes acroparaesthesias, angiokeratomas, corneal opacities and progressive renal, cardiac and cerebrovascular disease. Enzyme replacement is available.

Option by option

  • A. Glucocerebrosidase

    Glucocerebrosidase deficiency causes Gaucher disease with hepatosplenomegaly and bone disease.

  • B. Alpha-galactosidase A (correct)

    Correct. This enzyme deficiency causes Fabry disease with X-linked inheritance.

  • C. Hexosaminidase A

    Hexosaminidase A deficiency causes Tay-Sachs disease with a cherry-red spot.

  • D. Sphingomyelinase

    Sphingomyelinase deficiency causes Niemann-Pick disease with hepatosplenomegaly and neurodegeneration.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Biochemistry questions

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is B, Alpha-galactosidase A. Fabry disease is X-linked and results from alpha-galactosidase A deficiency, with accumulation of ceramide trihexoside.

Why is "Glucocerebrosidase" not the answer?

Glucocerebrosidase deficiency causes Gaucher disease with hepatosplenomegaly and bone disease.

Why is "Hexosaminidase A" not the answer?

Hexosaminidase A deficiency causes Tay-Sachs disease with a cherry-red spot.

Why is "Sphingomyelinase" not the answer?

Sphingomyelinase deficiency causes Niemann-Pick disease with hepatosplenomegaly and neurodegeneration.

What concept does this question test?

It tests Lysosomal storage disorders in Biochemistry. It causes acroparaesthesias, angiokeratomas, corneal opacities and progressive renal, cardiac and cerebrovascular disease. Enzyme replacement is available.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Lysosomal storage disorders?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.